BigDataStatMeth (version 1.0.3)

bdReduce_hdf5_dataset: Reduce Multiple HDF5 Datasets

Description

Reduces multiple datasets within an HDF5 group using arithmetic operations (addition or subtraction).

Usage

bdReduce_hdf5_dataset(
  filename,
  group,
  reducefunction,
  outgroup = NULL,
  outdataset = NULL,
  overwrite = FALSE,
  remove = FALSE
)

Value

List with components. If an error occurs, all string values are returned as empty strings (""):

fn

Character string with the HDF5 filename

ds

Character string with the full dataset path to the reduced dataset (group/dataset)

func

Character string with the reduction function applied

Arguments

filename

Character string. Path to the HDF5 file.

group

Character string. Path to the group containing datasets.

reducefunction

Character. Operation to apply, either "+" or "-".

outgroup

Character string (optional). Output group path. If NULL, uses input group.

outdataset

Character string (optional). Output dataset name. If NULL, uses input group name.

overwrite

Logical (optional). Whether to overwrite existing dataset. Default is FALSE.

remove

Logical (optional). Whether to remove source datasets after reduction. Default is FALSE.

Details

This function provides efficient dataset reduction capabilities with:

• Operation options:

  • Addition of datasets

  • Subtraction of datasets

• Output options:

  • Custom output location

  • Configurable dataset name

  • Overwrite protection

• Implementation features:

  • Memory-efficient processing

  • Safe file operations

  • Optional source cleanup

  • Comprehensive error handling

The function processes datasets efficiently while maintaining data integrity.

References

• The HDF Group. (2000-2010). HDF5 User's Guide.

See Also

• bdCreate_hdf5_matrix for creating HDF5 matrices

Examples

if (FALSE) {
library(BigDataStatMeth)

# Create test matrices
X1 <- matrix(1:100, 10, 10)
X2 <- matrix(101:200, 10, 10)
X3 <- matrix(201:300, 10, 10)

# Save to HDF5
fn <- "test.hdf5"
bdCreate_hdf5_matrix(fn, X1, "data", "matrix1",
                     overwriteFile = TRUE)
bdCreate_hdf5_matrix(fn, X2, "data", "matrix2",
                     overwriteFile = FALSE)
bdCreate_hdf5_matrix(fn, X3, "data", "matrix3",
                     overwriteFile = FALSE)

# Reduce datasets by addition
bdReduce_hdf5_dataset(
  filename = fn,
  group = "data",
  reducefunction = "+",
  outgroup = "results",
  outdataset = "sum_matrix",
  overwrite = TRUE
)

# Cleanup
if (file.exists(fn)) {
  file.remove(fn)
}
}